Is it wise to use edge loops and subdivision modifiers on high poly meshes?
Lower polycount is better performance-wise.
But sometimes it makes sense to sacrifice performance for ease of use. 



Bevel modifier
- easily adjustable edge width, great for hard surface modeling
- not suitable for complex corners and edges (creates overlaps)
- low-poly results

Subdivision Modifier
- easy to use, great for organic surfaces
- works almost anywhere
- hi-poly results  (4x more polygons with each level)

In reality they're often used together.

Let's compare
Same edge resolution, different face count.